Managing stroke risk post TIA - how urgent?

NICE guidance suggests (1):

Initial management of suspected and confifirmed TIA

• offer aspirin (300 mg daily), unless contraindicated, (with proton pump inhibitor cover where appropriate) (2) to people who have had a suspected TIA, to be started immediately
  
  
• refer immediately people who have had a suspected TIA for specialist assessment and investigation, to be seen within 24 hours of onset of symptoms
  
  
• do not use scoring systems, such as ABCD2, to assess risk of subsequent stroke or to inform urgency of referral for people who have had a suspected or confirmed TIA
  
  
• offer secondary prevention, in addition to aspirin, as soon as possible after the diagnosis of TIA is confirmed

Notes:

• the NICE committee agreed, based on their clinical experience and the limited predictive performance of risk scores, that all cases of suspected TIA should be considered as potentially high risk for stroke
  • also, because there is no reliable diagnostic test for TIA (the risk stratification tools are not diagnostic tests), it is important to urgently confirm or refute the diagnosis of a suspected TIA with specialist opinion
    • particularly so because in practice, a significant proportion of suspected TIA (30% to 50%) will have an alternative diagnosis (that is, TIA-mimic)
    • it was agreed that everyone who has had a suspected TIA should have specialist assessment and investigation within 24 hours of the onset of symptom
      
      
• ABCD2 algorithm(3,4) predicts a patient's very early risk of stroke following a TIA The score is calculated according to 5 important clinical features:

The corresponding 2 day risks for a subsequent stroke are:

The ABCD2 algorithm can be used to estimate the degree of urgency - however NICE now advise the need for review of all TIAs by a specialist within 24 hours (1):

• ABCD2 score 4-7:
  • these patients are at high risk of subsequent stroke
  • treatment with 300 mg aspirin daily should be started immediately
  • specialist assessment and investigations should be commenced within 24 hr of the onset of symptoms
  • this may require admission to hospital
  • further secondary prevention measures should be introduced once the diagnosis is confirmed
  • definitive secondary preventative therapy should be initiated within 2 weeks following the onset of symptoms
• ABCD2 score 0-3:
  • these patients are at lower risk of subsequent stroke
  • treatment with 300 mg aspirin daily should be started immediately
  • specialist assessment and investigations should be commenced within 1 week of the onset of symptoms
  • further secondary prevention measures should be introduced once the diagnosis is confirmed
  • definitive secondary preventative therapy should be initiated within 2 weeks following the onset of symptoms
• late presentation:
  • patients who present more than 1 week following the resolution of symptoms should be treated as lower risk

Reference:

• NICE (May 2019).Stroke and transient ischaemic attack in over 16s: diagnosis and initial management
• CKS. Stroke and TIA (Accessed 19/6/19)
• University of Southampton NHS Foundation Trust. TIA referral (Accessed 1/3/14)
• Johnston SC, Rothwell PM, Nguyen-Huynh MN, Giles MF, Elkins JS, Bernstein AL, Sidney S. Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack(2007) Lancet 2007;369: 283-92